Dental casting apparatus



Oct. 29, 1940. A, YANT|$ 2,219,538

DENTAL CASTING APPARATUS Filed June 16, 1939 2 Shets-Sheet 1 INVENTOReorye 1i X02175 ATTORNEY Oct. 29, 1 940. G YANT|5 2,219,538

DENTAL CASTING APPARATUS Filed June 16, 1959 2 Sheets-Sheet 2 as 1 as 76a? 88 6 INVENTOR I r ATTORNEY Registered Oct. 29, 1940 2 219 533 I VUNITED STATES PATENT OFFICE DENTALOASTING APPARATUS George A. Yantis,Elma, Wash. Application June 16, 1939, Serial No. 279,425

7. Claims. (01. 2z-s9.1

This invention relates tomechanism for casting tilting of the tiltablecrucible to cause themeltedmetals in investment material, More particugold to be delivered from the crucible to a casting larly, thisinvention relates to mechanism for investment. I I dental castings, asinlays, crowns, and partial. In melting metals for casting it hasbeenfound dentals, etc. that it is important to melt the gold and raise its5 l-ieretofore great difficulty has been experienced temperature alittle above the melting point bein theproduction of accurate dental.castings. A fore casting but not overheat it. If we are able perfectimpression in wax'of the cavity in a tooth. to cast at a certaincritical temperature, as above may be obtained, but because ofinaccuracies in described, we will greatly increase the strength 10 thecasting process, difiiculty has been obtained. and. ductilityofthecasting, and eliminate weak- 10 in reproducing a casting whichwillproperly fit ening pits and porous areas. This invention makes withinthe cavity in the tooth; One of thedim itp sible to d h automaticallyndin ur'un culties heretofore encountered has. been in obform,predictable results with every casting. taming theproper temperature andfluidity of the In my invention the fluid condition of the gold gold atthe time of casting. isthe determining feature in the control mecha- 15My invention provides means which are con-. nism for delivering the goldfrom the crucible to trolled by the fluid condition of the melted: goldthe casting investment. Alsoin my invention the (herein referred to. asgold, although, of course, temperature of the casting investment'ismainalloying metals are included to provide the proper tained. (by theuse of a rheostat, if necessary) at degree of hardnessand wearingqualities) to de-. the temperature to receive the melted gold, This 20termine the exact period at which the melted invention is in the natureof an improvement on gold is to be delivered to. the casting investment.my co-pending application Serial No. 204,617,al- While heretofore it hasbeen recognized thatthe lowed: February 8, 1939, Patent No. 2,171,778,fluid condition of the gold is important in deter- Thus, I am able in myinvention- 130 b n mining the proper time of casting;.no practical,melted gold. to. a certain critical temperature at 25 simple andefficient means have been produced the time ofcastingand at the-sametime to hold which will take advantage of thisprinciple. For' thetemperature of the investment at a certain example, the patent issued.to M. F. Patterson predetermined temperature while casting and-do DentalSupply Co. No. 1,767,023, issued June 24, it all automatically withouthelp from the oper- 1930, attempts to use electrodes, electrical conatorof the machine after it is once turned on. 30 tact between which iscarried by the melted gold- The above mentioned general objects of myin- The establishing of electrical communicationibee vention, togetherwith others inherent in thetween the electrodesis used to control theopersame, are attained by the mechanism illustrated ation-of acentrifugal casting machine, n h f ll wingr win s. h s me being pre- 5Such type of apparatus has proven impractical ferred exemplary forms ofembodiment of my in-- as the electrodes must be placed. in the meltingvention, throughout which drawings like referchamber and will attainimpractical temperatures ence numerals indicate like parts: for theelectrodes. For example, the electrodes. Figure 1: is a view partly inelevation and partly will attain temperatures which will cause theelecin. section: of casting apparatus constructed in ac- 40 trodes toalloy out and become apart of the castcordance with this invention,electrical devices 40 ing material. Any arcing between the electrodesconnected therewith- 1 being diagrammatically will cause an oxidation ofthe gold. Theelecshown;

trodes must be spaced apart such relatively short 7 Fig. 2 is afragmentary cross sectional view of distances because of the smallamount of melted the'same taken substantially on broken line 2-2 goldpresent so that serious problems are involved of Figure 1, parts beingshownin elevation; 45 in maintaining the electrodes; Fig. 3: isv afragmentary enlarged cross section In my invention I employ a tiltably:mounted taken substantially on broken line 33 of Fig. 2; gold meltingcrucible, the floor of which, is in- Fig. 4' is a detached, plan view,with parts broken clined relative to the horizontal. The gold-to beaway, of the solenoid operated trip'device shown melted is placed on ahigher portion ofthe inby dotted linesin Figure l; 50 clined floormember and. whenthe gold becomes Fig; 515 a. detached plan view of aswitchmech melted so it will flow down the inclined floor meme anismshown in Figure '1; her, the gold serves to tilt the crucible. At thisFig. 6; is a view partly in elevation and partly in point the gold is atthe proper fluidity for casting; sectionof another casting apparatusconstructed and l employ means which are controlled by the inrac ordancewith this invention, parts being 55"" broken away and electrical devicesconnected therewith being diagrammatically shown;

Fig. 7 is a fragmentary enlarged sectional view taken substantially onbroken line 1-1 of Fig, 6;

Fig. 8 is a view partly in section and partly in elevation and partlybroken away of still another casting apparatus constructed in accordancewith my invention, electrical devices connected therewith beingdiagrammatically shown;

Fig. 9 is a detached plan view of the crucible employed in the apparatusshown in Fig. 1; and

Fig, 10 is a sectional view of said crucible on broken lines IG! 3 ofFig. 9. 1

Figs, 1 to show an embodiment of this invention in which a tiltablymounted crucible is disposed within a swingingly mounted cruciblehousing and a casting furnace is removably secured to the cruciblehousing and swings with the crucible housing. In this construction thecrucible housing and casting furnace are supported substantiallyhorizontally while the metal is being melted and the casting or pouringof the metal, after it is melted, is accomplished by swinging thecrucible housing and casting furnace downwardly into a position in whichthe crucible housing is above the casting furnace so that the moltenmetal will be delivered into investment means in the casting furnace.

Figs. 1 to 5 show a crucible housing l5 having a crucible chamber l4therein. The crucible housing 15 has a transverse tube l6 embeddedtherein near one end. The tube I6 is pivotally mounted on a horizontaltubular bearing member I'i that issupported by an upright panel [8 in anupright support IS. The tubular bearing member I i also serves as aconduit for air or gas under pressure which is delivered thereto throughconduit means 20 (Fig. 2) having a control valve 21 therein. Thecrucible housing 15 has a lining 22 therein within which is provided thechamber M for the reception of a crucible 23. The lining 22 has electricheating means 24 embedded therein. The preferred form of the crucible 23is also shown in Figs. 9 and 10.

A casting furnace 25 is releasably and removably connected with thecrucible housing I5 in end to end relation. Preferably a releasablehinge means 26 and a releasable securing means 27 are used to connectthe casting furnace 25.

with the crucible housing l5. The casting furnace 25 has a lining 28 ofrefractory material within which is provided a heating chamber 29 forthe reception of an investment ring 30 having investment material 3|therein. Electric heating means 29' is provided in connection withthe-heating chamber 29.

A pyrometer 32 is provided in the casting furnace to accurately recordthe temperature of the casting investment material 3|. A rheostat can beprovided to hold the temperature of the investment at a predeterminedtemperature until ready for the casting operation to take place. Theremaining structure of the casting furnace 25 is shown and described indetail in my said co-pending application.

The crucible 23 is preferably formed of heat resistant non-metallicmaterial, such as porcelain. This crucible 23 is pivotally supportedwithin the chamber M on a fulcrum member 33.

1A hook shaped member 34 on the bottom portion of the crucible 23engages with the upper hook shaped end portion of the fulcrum member 33and helps prevent displacement of the crucible 23. The forward portionof the crucible is preferably inclined to facilitate pouring of moltenmetal therefrom and said inclined portion is positioned at the mouth ofthe chamber M. A crucible positioning means in the form of a shoulder 35in the crucible housing is provided for the rear end portion of thecrucible to rest on when the parts are in the position shown in Fig. 1.The crucible floor member 36 on which the metal to be cast is melted isinclined, relative to the horizontal, downwardly from the rear towardthe front end of the crucible when the crucible is supported in themetal melting position shown in Fig. 1. This incline of the cruciblefloor member 33 may be attained in different ways, provided that saidfloor portion 36 is always inclined sufficiently, when the crucible isin a metal melting position, so that when metal is placed on a higherportion of said floor member and melted it will flow by gravity to alower portion of said floor member. The shifting of weight that occursin the crucible when the metal melts and flows to the lower portion ofthe crucible is sufficient to tilt the crucible on the fulcrum member 33and this tilting of the crucible is used to actuate electrical deviceswhich control the pouring or casting of the melted metal.

The distribution of the weight of the crucible and the balance of thecrucible on its fulcrum are such as to insure the tilting of saidcrucible from the initial or metal melting position, shown by full linesin Fig. 1, to a second position shown by dot and dash lines in Fig. 1,when the smallest amount of metal that will ordinarily be used becomesliquid and flows along floor member 36 from a higher to a lower portionof the crucible. The second position into which the crucible will bemoved, shown by dot and dash lines in Fig. 1, is a switch operatingposition which controls the casting of the melted metal. Controlling thecasting or pouring of the metal by the flow of the metal from one partto another of the crucible insures that the metal will have to be fullyand completely melted and in proper condition for casting before theactual casting or pouring can take place.

Preferably the floor member 36 is provided with a restricted passagewayformed between walls 36' (see Figs. 9 and This passageway serves torestrict the flow of the metal until it is all fluid.

A pyrometer member 31 may be provided in the crucible housing to give anaccurate reading of the temperature within the crucible chamber M.

The housings I5 and 25 are spaced outwardly from the panel I 8, as bestshown in Fig. 2, so that they will swing clear of certain electricalcontrol devices on said panel.

The electrical control means controlled by the tilting of the crucible23 comprises a switch lever 38 fulcrumed on a pivot 38. One end ofswitch lever 38 is positioned to be engaged by a portion of the crucible23, as shown in Fig. 1, so that the switch lever 38 will be angularlymoved by movement of the crucible produced by the melting and flowing ofthe metal within said crucible. The other end portion of switch lever 38carries a contact member 39 positioned to electrically contact anothercontact member 40 when the switch lever 38 is angularly moved by upwardmovement of the portion of the crucible 23 which engages therewith. Theswitch lever 38 is arranged, as by balance of weight, so that it willmaintain the switch comprising contacts 3940 open except when said lever38 is moved into a closed switch position by crucible 23.

Two circuit"wires 4| connect the contact members 39 and 40 with aretarded relay 42: in

such a manner that the retarded relay 42 will be: energized by theclosing of the switch "co'mprising contact members 39 and 41L Circuitwires 4| may be connected with any suitable source of energy, not shown.Also a control switch capable of either manual or automatic operation ispreferably interposed in circuit wires 4| as hereinafter described.Switch lever 38 and contacts 39 and 40 may be operativelyfdisposed in apassageway 43 provided in the wall and. lining of crucible housing I5and extending from the crucible chamber I4 t tubes I6 and H, ashereinafter described. 7

The retarded relay 42 controls the opening and closing of a switch 44that is connected in circuit with a solenoid 45 by circuit wires 46which extend to any suitable source of energy, not shown. The solenoid45, Figs. 1 and 4, has a plunger 4'! that is connected by a pivot 48with one arm of a bell crank lever 49. The other arm of the bell cranklever and out of a supporting position relative to a lug 55 on thecrucible housing I5. The bell crank lever 49 is mounted on a pivot 5|that is supported by a bracket 52 from a panel I8. The bell crank lever49, when positioned under the 1115; member 58, is adapted to support thehousing parts in the horizontal position shown in Fig. 1. I

The control means for the heating element 24 in the crucible housing andthe heating element 29 in the casting furnace are preferably as follows:Electrical conductors 53 from a suitable source f energy, not shown, areconnected with the heating element 24. Two switches 54 and 55 areinterposed in the conductors 53 in circuit with the heating element 24.Similarly electrical conductors 5% connect heating element 29' of thecasting furnace with a source of energy, not shown, and two switchesi'land 58 are interposed in the conductors 56 in circuit with heatingelement 29'. The twoswitches 54 and El, diagrammatically shown in Fig.1, are man ually controlled switches of well known form of providingelectrical connections for medium heat and having capable high, low andoii or open switch positions. The two switches.

55 and 5B are capable of being operated both manually and by theswinging movement of the casting apparatus housings i5 and 25. Anotherswitch 59 similar to switches 55 and 58 ispreferably interposed inconductors 4| which control the supply of current to the retarded relay42.

The switch 55 is more fully shown in Fig. 5.

The switches 58 and 55 are similar to the switch 55 and the showinganddescription of the switch will apply equally well to the switches 58and 55. The switch 55, Fig. 5, comprises a fixed contact member 6|; anda movable contact member 52 mounted on a pivot 63 and pivotally movableinto open or closed switch position relative to the fixed contact member62. When contact member 52 is in the position shown by full lines inFig. 5, the electrical circuit through contact members 6i62 will beclosed and the heating element 24 may be energized. Also for thisposition of contact member 62, the insulated,

end portion. 54 of the contact member 62 is positioned in the path ofmovement of the lug 50 on the crucible housing l5, whereby it will beengaged by said lug 50 bers I5 and 25 swing thereby into the open 5dotted lines in Fig. 5.

downwardly and moved 'tch position shown by 45 is movable into as thetwo housing mem- This breaks the circuit to the heating coil 24 when thehousing members I5 and 25 swing downwardly into the metal casting orpouring position. Also the contact member 62-64 may be manually movedinto the open switch position shown by dotted lines in Fig. 5,regardless of the position of the housings I5 and 25.

The contact member 62-64 may be moved manually to a closed switchposition shown by dot and dash lines in Fig. 5, in which closed switchposition it is out of the path of the lug 55 so that the circuit toelectric heater 24 may be maintained closed regardless of the positionof housing members I5 and 25.

Similarly the switches 58 and 59 will serve to electrically connect ordisconnect the heating element 29' and the retarded relay 42 from theirrespective circuits. The lugs 65 and 65 carried by housing member 25,shown by dotted lines in Fig. 1, function similarly as respects switches58 and 59 as lug 50 functions as respects'switch 55.

Pyr'orneter members 32 and 31 may be connected with a common indicator61 through a selectively operable switch means 68 which will cause themto respectively operate said indicator 61.

In the operation of the device shown in Figs. 1 to 5, inclusive, themetal 60 to be melted and cast is placed on a'higher portion of thecrucible floor member 36. The said crucible is properly positionedwithin the crucible housing I5 and the crucible housing I5 and castingfurnace 25 are supported by bell crank 49 in substantially a horizontalposition as shown in Fig. 1'. Tilting of the crucible 23, due to themelting and flowing of the gold therein, will close the switchcomprising contacts 39 to retarded relay 42. The energizing of theretarded relay 42 will close the circuit to the solenoid 45 and move thebell crank 49 into the releasing position shown by dot and dash lines inFig. 4; This will release the crucible housing and permit said cruciblehousing and the casting furnace to swing downwardly by gravity and cometo rest in a substantially vertical position. As the crucible housingand casting furnace swing downwardly the molten gold'in the cruciblewill be poured or cast into a suitable cavity in the investmentmaterial. The retarded relay 42 is capable of being set so that theclosing of the switch 44 will be delayed for a predetermined period oftime after the retarded relay 42 is energized. Also the restrictedpassage between walls 36' serve to restrict the metal until'the same isall melted.

' These provide for delaying the pouring of the molten metal for apredetermined time after it has become sufiiciently liquefied to flowfrom one portion of the crucible to another and insures that all of thegold will be completely melted and in a proper condition for castingbefore the casting operation takes place.

The tubular members It and H, upon which housing I5 is mounted forswinging movement, have ports I and II, see Figs. 1 and3. which. serveas means for automatically controlling the inlet of gas under pressureto the crucible chamber I4. This gas under pressure passes throughregistering ports I0 and H and functions to forc th 'melted metal intothe cavity in the investment material in casting. When the housingmembers I and 25 are in the horizontal position, the ports and II areout of registration and when the housing members I5 and '25 are and 45and supply energy in a vertical position, the ports 10 and II are inregistration.

Further description of the mode of operation of the devices shown inFigs. 1 to 5, inclusive, and particularly as to parts not hereinclaimed, may be found in my said copending application.

Fig. 6 shows this invention adapted to casting apparatus in which acrucible unit is movable in a circular path around a center and isadapted to be selectively positioned to deliver melted metal intoinvestment means in any one of a plurality of non-movable castingfurnaces positioned at equal radial distances from the center aboutwhich the crucible unit moves.

Much of the apparatus shown in Fig. 6 is similar to that disclosed in mysaid copending patent application, to which reference is made for acomplete description of mechanism shown in said Fig. 6, but not hereindescribed in detail.

The casting furnaces shown in Fig. 6 are similar in construction to thecasting furnace shown in Figs. 1 to 5, but are fixedly mounted, whereasthe casting furnace shown in Figs. 1 to 5 is swingly mounted.

The crucible of Fig. 6 and the operating mechanism connected therewithdiffers from that shown in Fig. 5 principally, in that the crucible ismovable into and out of registration with a fixedly supported castingfurnace.

Fig. 6 discloses a base I2 having a fixed upright tubular post 73thereon. A plurality of casting furnaces 25 are mounted on the base I2preferably with their axes at equal radial distances from the post 13.Each casting furnace 25 has a chamber 29, heated by an electric heater29' and adapted to receive an investment ring 39 with investmentmaterial 3I therein. Also each casting frunace has a pyrometer I4connected with an indicator 15 through conductors E6 and selectivecontact mechanism I7. Another conductor I6 connects a pyrometer 14 in acrucible housing It with the indicator I5 through the selective contactmechanism 17. Manually operated switches 19 control suit-able heatingcir cuits to heating elements 29' of the casting furnaces and to aheating element in the crucible housing I8. These switches preferablyeach provide for three speeds of heat and each have an open circuitposition.

The crucible housing I8 shown in Fig. 6 has a lining 8i provided with acrucible chamber 82,

having the heating element 95 in the wall thereof. A crucible 83 issupported within the chamber 82 by a fulcrum member 34 and hook shapedmember 85. The crucible 82 has three positions, first, a meltingposition shown by full lines in Fig. 6, in which it is supported withthe floor member 86 thereof at sufiicient incline to the horizontal toinsure that gold placed on a higher portion thereof will flow down saidinclined floor member to a lower portion thereof, second, an inclinedposition, shown by broken lines in Fig. 6, into which it is moved by themelted gold flowing on said inclined floor member from a higher to alower portion thereof, and third, a dumping position, shown by dot anddash lines in Fig. 6, in which said crucible is approximately uprightand delivers melted gold to a casting investment.

The means, controlled by the movement of the crucible from its saidfirst position to its second 1 position, for controlling the movement ofthe crucible into its discharging position comprises a thrust rod 87guided for vertical movement in a passageway 88 in the crucible housing18. Ribs 89 are provided on rod 81, see Fig. 7, to leave space aroundrod 81 for gas under pressure to flow through passageway 88 into chamber82. The lower end portions of the ribs 89 are adapted to engage with ashoulder 90 to limit downward movement of rod 81. The lower end of rod89 is positioned in close proximity to the upper edge of the crucible 83when said crucible is in the metal melting position shown by full linesin Fig. 6.

The upper end portion of rod 89 is positioned to engage with a resilientswitch member 9| and move said switch member 9I into contact withanother resilient switch member 92. Switch members 9I and 92 control acircuit through conductors 93 to a retarded relay 94. The retarded relay94 operates a switch 95 which controls a circuit through conductors 96to a solenoid 91. The solenoid 91 has a core member 98, provided with avalve 99 that is operable as respects a valve seat I09. Also core member98 is preferably connected with switch member 92.

A gas tight housing IUI encloses the solenoid 91 and has a gas tightconnection with the top end portion of the crucible housing I8. Also thechamber I02 in which the core member 98 operates is gas tight and theupper end portion of said chamber I02 is connected with a gas inletconduit I 93. Conduit I03 has a valve I04 and is connected with aflexible conduit I95. The flexible conduit I95 preferably extendsdownwardly through the tubular post I3 into the base I2 where it mayconnect with any suitable source of supply of gas under pressure, notshown. Also all of the circuit wires and conductors from the crucibleunit preferably extend downwardly through post 12.

The crucible housing I8 is supported from the post 12 by a two part armmeans I66 which is angularly and vertically adjustable on the post I2and which permits the crucible housing I8 to be angularly moved on anaxis perpendicular to the post 12. This provides for moving the cruelblehousing 78 into and out of proper registration and operative engagementwith the several casting furnaces 23 and for angularly moving thecrucible housing I8 about the axis of the arm means I06 to facilitateinsertion and removal of the crucible and the material to be meltedtherein.

In the operation of the casting apparatus shown in Fig. 6, metal 69 tobe melted is placed on a higher portion of the floor member 86 of thecrucible 83 and said crucible is supported in the melting position shownby full lines in Fig. 6. When the metal 60 becomes liquid it will flowto a lower portion of the crucible, and in so doing, will shift theweight in the crucible and tilt the same into the second position, whichis the switch closing position shown by broken lines in Fig. 6. Thiswill move rod 8! upwardly and close the circuit through resilient switchmembers 9| and 92 to retard relay 94. However the weight of the solenoidcore member 98 resting on switch member 92 will arrest the movement ofthe crucible 83 at this point and hold the same in the said secondposition, shown by broken lines, and the metal will not be cast orpoured until after the retarded relay 94 operates. Retarded relays 94and 42 may not be necessary but are shown in case they are needed. Themay be long enough to insure that all of the metal has had time tobecome properly melted and to flow to the lower portion of the crucible.Thereafter, and at the end of the predetermined time, the retarded relay94 will close the switch 95, en-

delay thus provided tion of the floor member of the crucible III andergize the solenoid s1, and lift the core member 98. When core member 98is lifted, the weight of the crucible 83 and melted metal therein willfurther lift the rod 81' and free the crucible 83 and the crucible willtilt downwardly into a position as shown by dot and dash lines in Fig. 6and discharge the melted metal onto the investment material. The liftingof the core member 98 will open the valve 99 simultaneously with thepouring of the metal and this will admit gas under pressure to force themelted metal into a cavity in the investment material.

The casting apparatus shown in Fig. 8 comprises a crucible housing I'I,having a lining I08 provided with heating element means I09 and forminga crucible chamber IIO. A crucible III is p-ivotally supported withinchamber I I 0 by fulcrum means I I2 and hook like means H3. The crucibleIII has three operative positions, first, a metal melting position shownby full lines, second, a switch closing position shown by broken lines,and third, a metal pouring position shown by dot and dash lines. I

A casting furnace H4 having an investment ring I I5 and investmentmaterial I I6 therein cooperates with crucible housing I0'I to receivemelted metal from crucible III.

A bell crank lever I I1 pivoted on pivot means I I8 has one arm thereofpositioned to be engaged by the crucible III and the other arm thereofextending upwardly through a slot I I9 in the upper portion of thecrucible housing I01.

A housing I is mounted on the upper end portion of crucible housing I01and the upper end portion of bell crank lever II-I extends into thishousing I20. A resilient contact member I2I has one end portion movableinto and out of the path of movement of the upper end portion of thebell crank lever I IT. The resilient con-tact member l2I is connectedwith a plunger I22 of a solenoid I23, thus resilient contact member INis moved vertically with plunger I22 into and out of the. path of theupper end portion of bell crank arm H1. When bell crank arm IITI engageswith resilient contact member I2I it moves said contact member I2I intocontact with a fixed contact member I23, which is out of the path ofmovement of bell crank arm I II. This closes a circuit throughconductors I24 to a retarded relay I25. The retarded relay I25 controlsa switch I26 that is connected in the circuit wires I27I of the solenoidI23. This provides for first energizing the retarded relay I25 inresponse to movement of the bell crank lever II I and then after apredetermined time delay, energizing the solenoid I23.

A conduit I23 for gas under pressure communicates with thecruciblechamber IIO. A valve I29 in conduit I20 is connected by a lever I30 withsolenoid plunger I22 so that said valve will be operated in onedirection by movement of the plunger i222. A sprin I3I may be providedto operate the valve I29 in the other direction.

Two separate switch members I32 and I33 are connected with the lever I30and movable thereby into and out of electrical contact with other switchmembers I34 and I35 respectively. The

switch members I32, I33, I34 and I35 form two switches that areconnected by conductor means I35 and IE1 respectively with the heatingelement I92. in the crucible housing and with a heating element I38 inthe castingfur-nace H4 and are connected with any suitable source ofenergy (not shown). I

In the operation of the device shown in Fig. 8, metal 00 to be melted isplaced on "a higher porswitches said crucible I I I is supported in themelting position shown by full lines in Fig. 8. In this position theupper rear edge of the crucible is positioned below an arm of bell cranklever I I1. When the metal 00 becomes liquid it will flow to a lowerportion of the crucible and in so doing will shift the weight in thecrucible and tilt the crucible into the second position, which is theposition shownby broken lines in Fig. 8. In this second position theupper end portion of bell crank lever I I1 will engage with theresilient contact member I2I and move the same into electrical contactwith contact member I23. As the resilient contact member I2I ispositioned in the path of movement of the bell crank lever III the fixedcontact member I23 will prevent movement of the portion of springcontact member I2I and in turn serve as a stop for the bell crank leverI II. In this position the bell crank lever III will hold the crucible II I in the said second position until after the retarded relay I25 hasoperated to energize the solenoid I23 and move the plunger I22 and theresilient contact member I2I upwardly. Release of bell crank lever II'Iupon upward movement of resilient contact I2I releases the crucible I II and allows the same to tilt to the third position, which is the metaldischarging position shown by dot and dash lines in Fig. 8. In thislatter position metal will be discharged from the crucible III onto theinvestment H6 in the casting furnace I I4. In View of the fact that theother two modifications of this invention show in detail castingfurnaces, the casting furnace in Fig. 8 has been broken away. with thepouring of the melted metal the valve I29 in the conduit I28 is moved toan open posi-- tion and admits gas under pressure to force the meltedmetal into a cavity in the investment material l 6.' Also at this samesponse to upward movement of plunger I22, the

controlling the circuits to heating elements I09 and I39 are opened,thus deenergizing said elements.

In the various forms of this invention I have provided a tiltable goldmelting crucible. An inclined floor member is carried by this crucible.The gold to be melted is placed on a higher portion of the inclinedfloor member. As the gold becomes .melted it will flow down the inclinedfloor member and cause the tiltably mounted crucible to assume a secondposition. Upon the tiltably mounted crucible assuming. its secondposition, electric switch means are energized.

These electric switch means are positioned in a,

control circuit tocontrol the delivery of the gold to a casting furnace.Preferably a retarded relay to provide time delay is used so that thegold will be fully melted and in the proper fluid condition before it isdelivered from the crucible into the casting furnace. Upon the deliveryof the gold into the casting furnace, gas is introduced under pressureto force the gold into a cavity in'investment means in the castingfurnace.

Obviously, changes may be made in the forms, dimensions and arrangementof the parts of my invention, without departing from the principlethereof, the above setting forth only preferred forms of embodiment.

I claim:

1. In a device of the class described, a pivotally mounted housing; atiltably mounted crucible in said housing; an inclined fioor membercarried by said crucible and on which gold time and in ree.

Simultaneously 35 to be melted may be placed; means mounting saidcrucible for movement between a first position in which gold to bemelted is supported on a higher portion of said inclined floor memberand a second position into which the crucible is moved by flowing of themelted gold down said inclined floor member; casting investment meanscarried by said pivotally mounted housing in a receiving position asrespects said crucible when said housing is pivotally moved; and meanscontrolled by the movement of said crucible for pivotally moving saidhousing and delivering melted gold from said crucible into said castinginvestment.

2. In a device of the class described, a housing member; a castinginvestment in said housing member; a movably mounted crucible in saidhousing member provided with an inclined floor member and operativelypositioned relative to said casting investment to move to a golddischarging position as respects said casting investment; cruciblemounting means movably mounting said crucible to provide two goldmelting and retaining positions and a gold discharging position, a firstgold melting and retaining position in which gold to be melted issupported on a higher portion of said inclined floor member, a secondgold melting and retaining position into which the crucible is moved bythe flowing of melted gold down said inclined floor member, and a golddischarging position in which gold may be discharged into said castinginvestment; and crucible gold discharging means controlled by themovement of said crucible to its said second gold melting and retainingposition for delivering melted gold from said crucible to said castinginvestment.

3. In a device of the class described, a housing member; a castinginvestment in said housing member; a movably mounted crucible in saidhousing member provided with an inclined floor member and operativelypositioned relative to said casting investment to move to a golddischarging position as respects said casting investment; cruciblemounting means movably mounting said crucible to provide two goldmelting and retaining positions and a gold discharging position, a firstgold melting and retaining position in which gold to be melted issupported on a higher portion of said inclined floor member, a secondgold melting and retaining position into which the crucible is moved bythe flowing of melted gold down said inclined floor member, and a golddischarging position in which gold may be discharged into said castinginvestment; means forming a restricted passageway on said inclined fioormember positioned in the path of flow of the melted gold and limitingthe movement of the gold until it is fully melted; and crucible golddischarging means controlled by the movement of said crucible to itssaid second gold melting and retaining position for delivering meltedgold from said crucible to said casting investment.

4. In a device of the class described, a housing member; a castinginvestment in said housing member; a movably mounted crucible in saidhousing member provided with an inclined floor member and operativelypositioned relative to said casting investment to move to a golddischarging position as respects said casting investment; cruciblemounting means movably mounting said crucible to provide threepositions, a first gold melting and retaining position in which gold tobe melted is supported on a higher portion of said inclined floormember, a second gold melting and retaining position into which thecrucible is moved by the flowing of melted gold down said inclined floormember, and a gold discharging position in which the crucible is movedby gravity when released; and crucible releasing means controlled by themovement of said crucible to its said second gold melting and retainingposition for releasing said crucible and permitting the delivering ofmelted gold from said crucible to said casting investment.

5. In a device of the class described, a housing member; a castinginvestment in said housing member provided with a cavity therein; amovably mounted crucible in said housing member provided with aninclined floor member and operatively positioned relative to saidcasting investment to move to a gold discharging position as respectssaid casting investment; crucible mounting means movably mounting saidcrucible to provide two gold melting and retaining positions and a golddischarging position, a first gold melting and retaining position inwhich gold to be melted is supported on a higher portion of saidinclined floor member, a second gold melting and retaining position intowhich the crucible is moved by the flowing of melted'gold down saidinclined floor member, and a gold discharging position in which gold maybe discharged into said casting investment; and crucible golddischarging means controlled by the movement of said crucible to itssaid second gold melting and retaining position for delivering meltedgold from said crucible to said casting investment, said meanscomprising gas pressure discharging means urging the melted gold intothe cavity within the casting investment.

6. In a device of the class described, a housing member provided with acrucible receiving chamber and with an opening for the inserting andremoving of a crucible therethrough; a casting investment in saidhousing member; a crucible removably and movably mounted in saidcrucible receiving chamber and provided with an inclined floor memberand operatively positioned relative to said casting investment to moveto a gold discharging position as respects said casting investment;crucible mounting means movably mounting said crucible to provide twogold melting and retaining positions and a gold discharging position, afirst gold melting and retaining position in which gold to be melted issupported on a higher portion of said inclined floor member a secondgold melting and retaining position into which the crucible is moved bythe flowing of melted gold down said inclined floor member, and a golddischarging position in which gold may be discharged into said castinginvestment; and crucible gold discharging means con-trolled by themovement of said crucible to its said second gold melting and retainingposition for delivering melted gold from said crucible to said castinginvestment.

'7. In a device of the class described, a housing member; a castinginvestment in said housing member; a movably mounted crucible in saidhousing member provided with an inclined floor member and operativelypositioned relative to said casting investment; and crucible golddischarging position as respects said casting investment; cruciblemounting means movably mounting said crucible to provide two goldmelting and retainingpositions and a gold discharging position, a firstgold melting and retaining position in which gold to be melted issupported on a higher portion of said inclined floor member, a secondgold melting and retaining position mm which the crucible is moved bythe flowing of melted gold down said inclined floor member,

moved to its said second gold melting and retaining position; andcrucible gold discharging means controlled by said electrical switchmeans for delivering meltedig old from said crucible to said castinginvestment.

" GEORGE A. YAN'I'IS.

